Argument Champion, a game that uses logical connections between words to pwn your opponent.
The Adventures of Fallacy Man, from Existential Comics.
Conversational Terrorism Protect yourself from responding to or using these rhetorical cheats. (via the lovely boingboing)
I just posted a pretty weak link on unsound and fallacious arguments. Here's a better one. If you participate in debate on the net, you probably ought to read this, so you know *how* they're snowing you.